Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
  • If you want to search an entire area code regardless of activity, leave both the next and past days fields set to zero.

Switch: SFLDMIMK0MD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
313-261 1 Detroit Zone 1 MI 478J NUSO, LLC 340   2023-12-11   
313-385 A Detroit Zone 1 MI 478J NUSO, LLC 340      
313-385 1 Detroit Zone 1 MI 478J NUSO, LLC 340   2020-06-20   
313-462 3 Detroit Zone 1 MI 478J NUSO, LLC 340   2024-07-10   
313-872 8 Detroit Zone 1 MI 478J NUSO, LLC 340   2023-12-11   

Last updated: Thu, 20 Nov 2025 13:34:34 UTC

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